ShoeGeometry

Brooks Glycerin Flex

Daily trainerRoadNo plate2026Men'sCurrent

At a glance

Heel-to-toe drop
6 mmDerived
Stack, heel / forefoot
36 / 30 mmStated
Weight
250 gStatedUS M9
Plate
No plate
Toe rocker
35 % of lengthest.photos 35–43 %
Heel bevel
9.6 % of lengthest.photos 9–10 %
Stiffness / firmness
22 / 75 of 100Derived
Primary foam
DNA Tuned (dual-density supercritical)

How it compares

  • Brooks Glycerin Flex's heel-to-toe drop is 6 mm, about the catalogue median of 6 mm (25% of the 179 other current shoes are lower).
  • Brooks Glycerin Flex's heel stack is 36 mm, thinner than the catalogue median of 38 mm (28% of the 176 other current shoes are thinner).
  • Brooks Glycerin Flex's forefoot stack is 30 mm, thinner than the catalogue median of 31.5 mm (33% of the 171 other current shoes are thinner).
  • Brooks Glycerin Flex's weight is 250 g, lighter than the catalogue median of 269 g (29% of the 167 other current shoes are lighter).
  • 4 shoes with similar geometry from other lines.

Differences smaller than the precision of the sources (about 1 mm of stack, 8 g, or the spread between photos for photo estimates) are reported as about the same.

Specifications

Heel-to-toe drop
Derived
6mm
MediumCalculated
Heel stack
Manufacturer stated
36mm
LowSpec listingbrand figure, reported by Believe in the Runsource
Forefoot stack
Manufacturer stated
30mm
LowSpec listingbrand figure, reported by Believe in the Runsource
Weight
Manufacturer stated
250g
MediumSpec listingbrand figure, reported by Believe in the RunUS M9source
Plate
No plate
Primary foam
DNA Tuned (dual-density supercritical)
List price
$170

Geometry

Catalogue average: heel 38 mm, forefoot 32 mm, toe rocker 35 %Brooks Glycerin Flex: heel 36 mm, forefoot 30 mm (drop 6 mm); toe rocker 35 % of length, radius 61 % of length; heel bevel 10 % of length, 27 mm high at the back, ending behind the heel bone (only the back edge is rounded).36 mm30 mmUnder the centre of the heel bone: 12 % of length from the heel, where heel stack is measuredheel boneHeel contact: the sole is within 4.5 mm of the ground from 10 % of length (foam compresses more under load), ending behind the heel bone (only the back edge is rounded)heel bevel 10 %Toe rocker: the front 35 % of the length curves up (the curve leaves the ground 65 % of length from the heel)toe rocker 35 %toeheel
Front: toe rocker shorter longerRear: heel stack lower higher not measured
Dashed: average of the catalogue
Illustrative profile, not a photograph or scan: drawn to scale for a 300 mm shoe from published stack heights and photo estimates of the unloaded shoe (under body weight the foam compresses and the curves flatten). The grey upper is a generic outline, not this shoe’s. Brooks Glycerin Flex: heel 36 mm, forefoot 30 mm (drop 6 mm); toe rocker 35 % of length, radius 61 % of length; heel bevel 10 % of length, 27 mm high at the back, ending behind the heel bone (only the back edge is rounded). Heel bone: 12 % of length from the heel, where heel stack is measured. Heel bevel and toe rocker are marked where each curve meets the ground; for the heel that is where the sole comes within 4.5 mm of the ground, which foam compression closes under body weight.

Percent values are relative to shoe length so they compare across images and sizes; widths in millimetres are lab measurements from the cited source, while toe tip and heel heights in millimetres are photo estimates converted for a men’s US 9 (assumed 300 mm long), so approximate. See how rocker geometry is defined.

Toe rocker
AI estimated
35%

4 photos range 35–43 %; shown is one of the two that agree most closely.

LowSide photosource
Rocker radius
AI estimated
61%

4 photos range 45–61 %; shown is one of the two that agree most closely.

LowSide photosource
Rocker rise angle
AI estimated
23deg

4 photos range 23–25 deg; shown is one of the two that agree most closely.

LowSide photosource
Toe tip over ground
AI estimated
42mm*

4 photos range 38–44 mm; shown is the average of the two that agree most closely (* the photos disagree by more than usual).

LowSide photosource
Rocker angle at toe
AI estimated
49deg

4 photos range 46–49 deg; shown is one of the two that agree most closely.

LowSide photosource
Visible rocker lift onset
AI estimated
72.6%

4 photos range 72.5–76.8 %; shown is one of the two that agree most closely.

LowSide photosource
Toe spring (relative)
AI estimated
18%

4 photos range 16.1–18 %; shown is one of the two that agree most closely.

LowSide photosource
Heel bevel length
AI estimated
9.6%

4 photos range 9.1–9.6 %; shown is the average of the two that agree most closely.

LowSide photosource
Heel bevel height
AI estimated
27mm*

4 photos range 21–27 mm; shown is the average of the two that agree most closely (* the photos disagree by more than usual).

LowSide photosource
Midsole width (forefoot)
Externally measured
115.7mm
MediumLab testsource
Midsole width (heel)
Externally measured
97.2mm
MediumLab testsource
Toe box shape
AI estimated
74%

2 photos range 73–76 %; shown is the average of the two that agree most closely.

LowTop photosource
Interior forefoot width
Externally measured
93.9mm
MediumLab testsource
Toebox width
Externally measured
69.1mm
MediumLab testsource

Stiffness

Longitudinal stiffness
Derived
22/ 100

Lab reading: 12.2 N, force to bend the shoe 30° (lab bending test); the score is our 0–100 rescaling of it.

MediumLab flex testsource
Midsole firmness
Derived
75/ 100

Lab reading: 39.9 Asker C, midsole durometer reading (higher = firmer); the score is our 0–100 rescaling of it.

MediumLab durometersource

How it compares

Appears in:Longer toe rocker

Compare:Brooks Glycerin Flex vs Hoka Rincon 4Brooks Glycerin Flex vs Saucony Procyon Max

Wrong value? Missing data? Tell me
Stored only to improve the site; see privacy.

Sources

  • Brooks Glycerin Flex Review: Natural Movement In a Max Package | Believe in the RunreviewBelieve in the Runaccessed 2026-10-04open ↗
  • brooks-glycerin-flex medial product photoimageRunning Warehouseaccessed 2026-10-04open ↗
  • brooks-glycerin-flex medial product photoimageRunning Warehouseaccessed 2026-10-04open ↗
  • brooks-glycerin-flex lateral product photoimageRunning Warehouseaccessed 2026-10-04open ↗
  • brooks-glycerin-flex lateral product photoimageRunning Warehouseaccessed 2026-10-04open ↗
  • Cut in half: Brooks Glycerin Flex Review (2026) | RunRepeatlabRunRepeataccessed 2026-10-04open ↗
  • brooks-glycerin-flex sole product photoimageRunning Warehouseaccessed 2026-10-04open ↗
  • brooks-glycerin-flex top product photoimageRunning Warehouseaccessed 2026-10-04open ↗
Technical detail: every recorded value, method and version (31)

All approved observations

Every recorded value, including superseded ones. The displayed value per metric is chosen by precedence (measured › stated › derived › AI estimated), then confidence, then recency. 63 further observations awaiting review.

MetricValueClassConfidenceMethodSourceRecorded
Heel-to-toe drop6 mmDerivedMediumCalculated—2026-10-04
Heel stack36 mmStatedLowSpec listingBelieve in the Run2026-10-04
Forefoot stack30 mmStatedLowSpec listingBelieve in the Run2026-10-04
Weight250 g (US M9)StatedMediumSpec listingBelieve in the Run2026-10-04
Weight249 g (US M9)StatedMediumSpec listingBelieve in the Run2026-10-04
Rocker apex64.6 %est.LowSide photoRunning Warehouse2026-10-04
Rocker apex64.8 %est.LowSide photoRunning Warehouse2026-10-04
Rocker radius61 %est.LowSide photoRunning Warehouse2026-10-04
Rocker radius60 %est.LowSide photoRunning Warehouse2026-10-04
Rocker rise angle23 degest.LowSide photoRunning Warehouse2026-10-04
Rocker rise angle23 degest.LowSide photoRunning Warehouse2026-10-04
Rocker angle at toe49 degest.LowSide photoRunning Warehouse2026-10-04
Rocker angle at toe49 degest.LowSide photoRunning Warehouse2026-10-04
Toe tip over ground42 mmest.LowSide photoRunning Warehouse2026-10-04
Toe tip over ground42 mmest.LowSide photoRunning Warehouse2026-10-04
Visible rocker lift onset72.6 %est.LowSide photoRunning Warehouse2026-10-04
Visible rocker lift onset72.5 %est.LowSide photoRunning Warehouse2026-10-04
Toe spring (relative)18 %est.LowSide photoRunning Warehouse2026-10-04
Toe spring (relative)17.6 %est.LowSide photoRunning Warehouse2026-10-04
Heel bevel length9.6 %est.LowSide photoRunning Warehouse2026-10-04
Heel bevel length9.6 %est.LowSide photoRunning Warehouse2026-10-04
Heel bevel height27 mmest.LowSide photoRunning Warehouse2026-10-04
Heel bevel height27 mmest.LowSide photoRunning Warehouse2026-10-04
Midsole width (forefoot)115.7 mmMeasuredMediumLab testRunRepeat2026-10-04
Midsole width (heel)97.2 mmMeasuredMediumLab testRunRepeat2026-10-04
Toe box shape73 %est.LowTop photoRunning Warehouse2026-10-04
Toe box shape76 %est.LowTop photoRunning Warehouse2026-10-04
Interior forefoot width93.9 mmMeasuredMediumLab testRunRepeat2026-10-04
Toebox width69.1 mmMeasuredMediumLab testRunRepeat2026-10-04
Longitudinal stiffness22 DerivedMediumLab flex testRunRepeat2026-10-04
Midsole firmness75 DerivedMediumLab durometerRunRepeat2026-10-04

Classes: Manufacturer stated · Externally measured · AI estimated · Derived · User reported. Hover a method for its identifier and algorithm version.

Source notes

  • Running Warehouse: sha256=5a27637e6ddadd60570e88587eba9e98a9b7adda209e905c37014bb0f8cc9a5f; 0.3
  • Running Warehouse: sha256=fba9b1cf20a7fb918716a4bda557144a88f91c73ab8e77e7f3b6c8e6082867cb; 0.3
  • Running Warehouse: sha256=30172dcd9d21c4a6dd3a60fa2bfb5cb07df7b2bc481df3e076a30300f692b5c3; 0.3
  • Running Warehouse: sha256=e7498c95dc89221d14810e60c50098a62dec4f4a2b42554614c522d4d3be4df0; 0.3
  • Running Warehouse: sha256=2919bc5b8f3d77cc6abf04be8a8607ecfd9114639774d3cc5e2462ed832fd46d; 0.1
  • Running Warehouse: sha256=16889712142051e5eb12c84bd6d172c5c4a1967d804ea9cd5dae3c9a090df5b2; 0.1

Shoes with similar geometry

Compare these →

Closest current models from other lines by stack, drop, rocker, toe height, stiffness, firmness, weight and width, whichever both shoes have.

Side profile illustration of the Brooks Launch 12
Brooks
Launch 12
Daily trainer · No plate
Drop
8 mm
Heel
35 mm
Toe rocker
34%

vs this shoe: 2 mm more drop

Side profile illustration of the Adidas Adizero Boston 13
Adidas
Adizero Boston 13
Tempo · Plate unknown
Drop
7 mm
Heel
37 mm
Toe rocker
35%

vs this shoe: 5 mm wider base · stiffer

Side profile illustration of the VJ FZN Aerofly
VJ
FZN Aerofly
Road/trail hybrid · Rock plate
Drop
8 mm
Heel
38 mm
Toe rocker
—

vs this shoe: 2 mm more drop

Side profile illustration of the Hoka Mach 7
Hoka
Mach 7
Daily trainer · No plate
Drop
5 mm
Heel
37 mm
Toe rocker
38%

Very close on every shared measure